April 3, 2020
Like many diseases before it, including Spanish influenza, HIV, Ebola, and SARS, the 2019 coronavirus disease (COVID-19) pandemic originated in animals. We need a synchronized effort from professionals of public health, medicine, veterinary science, environmental science, translational research, and public policy to improve infrastructure for studying, preventing, and managing emerging infectious diseases that come from animals.
About 61% of infectious diseases in humans are zoonotic, meaning they come from animals. Human behaviors, such as settlement expansion, increased livestock ownership, international travel, and wildlife trading, are known to contribute to the emergence of novel zoonotic diseases. Unfortunately, research shows that more zoonotic diseases already exist in bat populations and are ready to infect humans if given the right opportunity. Therefore, the human behaviors contributing to the emergence of these diseases must be changed in order to prevent future public health crises.
One human activity contributing to the emergence of diseases is wildlife hunting, trading, and consumption The first cases of COVID-19 in humans has been linked to the Huanan “wet market,” where live wild game and wild meats were sold in Wuhan, Hubei Province, China. The virus causing COVID-19 likely lives naturally in bats. Research is ongoing, but the virus most likely jumped from bats to an intermediate host, Malayan pangolins, which was traded at the Huanan market, and then to humans. Professor Travis, a researcher of zoonotic diseases at the University of Minnesota, explained the trade of “bushmeat” (wild game meat) in his “Forest to Fork” presentation. He explained that the outbreaks of several diseases, including HIV and avian influenzas, have been linked to bushmeat consumption and international trade. In order to prevent further infectious disease emergence from bushmeat, steps can be taken: stop wild game trading, as China has done since January 26, 2020, and improve disease surveillance infrastructure, particularly in poor and rural areas.
The emergence of zoonotic diseases is also closely intertwined with the climate changes seen worldwide, as many of the same human activities contribute to both problems. These drivers include land-use change, overuse of natural resources, and agricultural development. All of these independently, as well as synergistically, impact human and environmental health.
Climate change itself is also known to decrease the diversity of species in ecosystems. While more research is needed to better characterize the relationship between biodiversity (number of different species that exist in an ecosystem) and zoonotic disease, it is clear that climate change and the emergence of infectious diseases are happening concurrently with many of the same influencing factors.
At this point, there are changes that can be made to slow the emergence of further detrimental infectious diseases, including ramping up efforts around the world to combat climate change.
Attention must be immediately drawn to human behaviors and their consequences on environmental and human health. There are known diseases already in existence with the potential to cause future outbreaks in humans. Ongoing research about zoonotic disease needs to occur at institutions across the globe both during outbreaks and during times of relatively good health. We must continue to act to combat environmental change, monitor diseases in animal populations, and work to develop therapies that treat a broader variety of infectious diseases.